The present invention relates to a press-contact terminal fitting, and more specifically, the present invention relates to a structure of a press-contact terminal fitting comprising a press-contact section for press-fitting an end portion of a sheathed electric wire and holding strips for crimping the sheathed electric wire.
As one of press-contact terminal fittings of this type, a press-contact terminal fitting 3, as shown in FIG. 5, to be disposed in the housing 2 of the connector 1 to be connected to a circuit board (printed board) has been used. FIG. 6 is a cross sectional view taken along the line B--B of FIG. 5. The connector 1 is, as shown in the FIG. 5, disposed and fixed on the wiring board (printed board) 4. The connector 1 is provided with insertion legs 1A projecting from the bottom thereof for securing it to the wiring board 4 (refer to FIG. 6). In the housing 2 of the connector 1, there are provided a plurality of open-top chambers 2A for accommodating the sheathed electric wires 5 arranged in parallel. On one of side walls 2B of the housing 2, as shown in FIG. 5, there are provided openings 2C in communication with respective chambers 2A for leading out the sheathed electric wires 5.
The press-contact terminal fitting 3 is, as shown in FIG. 7, formed by punching and bending a metal plate, and provided with a press-contact section 6 for electrically press-contacting with the sheathed electric wire 5 and a holding section 7 for surrounding and holding the sheathed electric wire 5. Depicted by a reference numeral 8 in FIG. 7 is a connecting strip which projects downwardly when the terminal fitting is accommodated in the connector 1.
The press-contact section 6 of the press-contact terminal fitting 3 comprises, as shown in FIG. 7 and FIG. 8, a pair of opposed clamping plates 6A and 6B standing upwardly from both sides of the press-contact terminal fitting 3 for clamping the wire. The clamping plates 6A and 6B respectively include two each of press-contact blades 6C and 6D, which are bent inwardly so as to project toward each other. In this press-contact section 6, the sheathed electric wire 5 is press-fitted from above as shown in FIG. 8A, and the resin sheath 5A of the sheathed electric wire 5 is cut by the press contact blades 6C and 6D so that the press contact blades 6C and 6D are directly connected to the core conductive wire 5B of the sheathed electric wire 5.
The holding section 7 is composed of a pair of holding strips 7A and 7B standing upwardly from both sides of the press-contact terminal fitting 3. In order to hold the sheathed electric wire 5 with the holding section 7, as shown in FIG. 9A, the sheathed electric wire 5 is placed between the holding strips 7A and 7B and crimped by the use of a jig (punch) as shown in FIG. 9B. As a result, as shown in FIG. 9B, a pair of holding strips 7A and 7B are in press-contact with the resin sheath 5A to hold the sheathed electric wire 5.
The press-contact section 6 and the holding section 7 disposed behind thereof are connected by rectangular shaped connecting plates 3A shown by a hatched area in FIG. 7. The connecting plates 3A effect to reinforce and prevent the clamping plates 6A and 6B from being urged outwardly when the sheathed electric wire 5 is press-fitted between the clamping plates 6A and 6B.
However, when the related press-contact terminal fitting 3 is used to connect and hold the sheathed electric wire 5, the following problem is encountered.
After the sheathed electric wire 5 is press-fitted into the press-contact section 6 and an electrical connection of established, when the holding strips 7A and 7B on the holding section 7 are crimped as shown in FIG. 9B, a force to urge the clamping plates 6A and 6B in the direction shown by the arrow a is exerted in conjunction with the bending operation of the holding strips 7A and 7B. Therefore, the press-contact blades 6C and 6D may move closer with respect to each other and may cut off the core conductive wire 5B of the sheathed electric wire 5. On the contrary, in the case where the sheathed electric wire 5 is press-fitted into the press-contact section 6 after the sheathed electric wire 5 is held by bending the holding strips 7A and 7B, the core conductive wire 5B may be cut off because the distance between the press-contact blades 6C and 6D is decreased.